DSPORT Five Worst Engines

See our Top Ten Engines List

1) Mitsubishi 4G54B

It Sounded Good On Paper, But Failed To Deliver

The Mitsubishi 4G54B ranks as the number one worst engine to tune. Although it was the first Japanese production car engine with computer-controlled fuel injection and turbocharging, it left much to be desired. As one of the largest four cylinder engines of all time, this iron block, 8- or 12-valve, single cam engine suffered from a number of issues. Rather than employing port fuel injection, a multi point injection system comprised of a pair of fuel injectors located behind the throttle body delivered fuel. This of course led to sketchy at best distribution of fuel to each of the cylinders. The single overhead camshaft made adjustment to valve overlap impossible. Tuners and consumers soon learned that the 4G54 was also prone to head gasket failures. For an engine that displaced as much as the RB26, the small factory turbocharger wasn’t much help as the engine as a whole was simply underwhelming. Aftermarket support was also extremely limited, adding to the challenge of extracting more power. With the cards stacked against it, its no wonder that the 4G54B engine takes the cake on the wall of shame. Sorry die-hard Starion and Conquest fans that haven’t made the 4G63 swap. 4G54B OPINION WHAT’S HOT: • Factory Turbocharged • Large displacement 4-cylinder engine WHAT’S NOT: • Prone to head gasket failure • Dual fuel injectors located behind the throttle body; no port injection • Sounded really good on paper, but failed miserably to deliver • Small factory turbocharger • 8- or 12-valve cylinder head with single overhead camshaft delivered underwhelming performance • Low-flowing cylinder head • Restrictive intake manifold • Restrictive throttle body


Manufacturer: Mitsubishi
Years In Production: 1982-1990
Engine Code: 4G54B
Displacement (cc): 2,555.5cc
Bore & Stroke (mm): 91.1mm x 98mm
Peak Horsepower (@ RPM): 150-197 bhp
Peak Torque (@ RPM): 160 lb-ft
Pistons/Compression Ratio: 9.2:1
Block Material: Iron
Head Material: Aluminum
Valves / Springs / Retainers: 12 Valves
Throttle Body: Single
Ignition System: Distributor
Applications: 1983-1989 Mitsubishi Starion
1984-1986 Dodge Conquest
1987-1989 Chrysler Conquest


5 thoughts on “Five Worst Engines | Overhyped and Underengineered

  1. hyperbatic says:

    Your torque figure for the G54B is way off. It looks like you are quoting from Wikipedia, but that info is incorrect. Torque ranged from 185 lbs-ft in the non-intercooled versions to a final max of 234 lbs-ft in the 1988-89 TSi and ESi-R models.

    From a 1985 Car and Driver test of the intercooled ESi:

    From Hemmings:

  2. theflash says:

    Um, I take it you don’t know any RX-8 owners? Over it’s entire production, it actually had WORSE mileage than the turbo 13B from the FD and even FC RX-7. Look up 3-stage intake manifold and 9,000 rpm redline. This destroyed the mileage. The ECU had nothing to do with modifications not working, it was the side-ports that robbed the Rotary of it’s best quality: strong exhaust pulses. This is why bolt-on turbo kits such as the one from Greddy would only increase by 80 whp, where as the even the 25 year old 6 port NA 13B has been boosted to over 400whp, let alone 13B-T, 13B-RE & 13B-REW. Real built cars get new stand-alone ECUs anyway.

    1. Michael Ferrara says:

      You make a very strong case!

  3. Will Zuchero says:

    The L20ET was the first turbocharged car out of Japan, not the 4G64B. Even the L28ET was produced in 80′

  4. thatguy says:

    Um, well, my ’97 hardbody with ka24e is still going strong at 220k. 20 and 1/2 years. All minor repairs. No engine related repairs and vacuum and compression tests are all normal. None of my previous american vehicles (6) ever lasted past 5 years before they had to be junked as too expensive to fix. Never been very fast but very dependable. I’m not an engineer but I think part of the reason is how cool the engine runs. Fortunately I live in the desert southwest where I don’t need the heater that much otherwise it would be pain because the engine takes a long time to heat.

Comments are closed.

You may also like